1. Technical Field
The present invention relates to a spring manufacturing machine capable of manufacturing variety types of springs.
2. Description of Related Art
When manufacturing a coil spring using a spring manufacturing machine, a wire fed from a wire passage is bent and deformed by bringing it into contact with a bending die placed in the vicinity of the outlet of the wire passage. When manufacturing a coil spring with a gradually increasing outside diameter, the bending die which is in contact with the wire is moved in the wire feeding direction. Although the wire is in contact with the bending die at the center when the bending deformation of the wire is started, it comes into contact with the bending die at a position away from the center as the outside diameter increases. In order to bend and deform the wire, it is necessary to keep the wire in contact with the bending die, and therefore the bending die is caused to swing toward the center of the outside diameter as the outside diameter increases.
A conventional spring manufacturing machine comprises a first bending die mounting slide including a slide body disposed along the wire feeding direction and a swing member connected to the slide body; a drive source, connected to the first bending die mounting slide, for driving the first bending die mounting slide; second and third bending die mounting slides provided on the upper and lower sides, respectively, and inclined at an acute angle with respect to the feeding direction to manufacture right-hand and left-hand springs; a block body disposed on a front wall of a machine body and provided with a cam groove inclined at an acute angle with respect to the feeding direction; and a slider provided on the swing member to slide along the cam groove.
In this spring manufacturing machine, the bending die is mounted to an end of the swing member. When the slider is driven by the drive source and slides along the cam groove, the bending die mounted to the swing member moves in the feeding direction and also swings with the movement in the feeding direction and the swing of the swing member, so that it is possible to manufacture a coil spring with a gradually increasing outside diameter. When manufacturing a right-hand spring, the wire is brought into contact with the bending die mounted to the swing member and a bending die mounted to the second bending die mounting slide, and supported. When manufacturing a left-hand spring, the wire is brought into contact with the bending die mounted to the swing member and a bending die mounted to the third bending die mounting slide, and supported. Thus, since it is not necessary to support the wire in contact with a core provided on the front wall of the machine body, it is possible to prevent scratches from being made on the coil spring by the contact between the wire and the core (Japanese Patent Application Laid-Open No. 2005-118798).
In addition to the spring manufacturing machine disclosed in Japanese Patent Application Laid-Open No. 2005-118798, there is conventionally proposed a spring manufacturing machine comprising a bending die mounting slide with a slide disposed along the wire feeding direction and a swing piece mounted to the slide; and a drive source, connected to the swing piece, for swinging the swing piece.
In this spring manufacturing machine, the bending die is mounted to an end of the swing piece. By swinging the spring piece to a position where the bending die mounted to the end of the swing piece does not come into contact with the fed wire, it is possible to manufacture a spring requiring the formation of a straight portion, for example, a torsion spring having straight portions at both ends (see, Japanese Patent Application Laid-Open No. 2001-293533).